Material for and method of cleaning metal surfaces



Patented Feb. 26,

unrreo STATES PATENT OFFICE.

PERCY H. WALKER AND JOHN H. BOWEB, OF WASHINGTON, DISTRICT OF COLUMBIA.

MATERIAL FOR AND METHOD OF CLEANING METAL SURFACES.

No Drawing.

Application filed February 27, 1919. Serial No. 280,671.

FILED UNDER THE ACT OF MARCH 3, 1883, 22 STAT. L, 625.)

To all whom it more) concern:

Be it known that we, PERCY and JOHN H. Bownn,

citizens of States, residing at Washington,

Columbia,

H. WALKER the United District of have invented certain new and full, clear,

and exact description of the mvention, such as will enable others skilled in the art to which it appertains to make and use the same.

This application is made under the act of March 3, 1883, chapter 143 (22 Stat., 625) and the invention herein described and claimed may be used by the Government of the United States,

employees in the pro the United States, or United States, without royalty thereon.

This invention methods of cleaning moval of metal fouli ordnance,

or any of its oflicers or secution of work for by any person in the the payment of any relates to materials for and metal surfaces such as iron or steel, and more particularly to the refrom fire arms and such as rifle barrels, machine gun barrels, and rifled guns of all types.

" A principal object of the invention is to roduce an effective metal-cleanin which will attack an deposits of a metallic nature detrimentally affecting the surfaces without from metal surface to be cleaned. Another important object of the invention is to provide the active chemical ingrediem of the metal-clean ing solution in the which can be easily handled, and which transported can form of solid substances and easily be readily and accurately brought together with a necessary amount of a suitable solven effective cleaning liquid or ty e desired.

ile the invention in its broa t to produce an solution of the der aspects relates to the cleaning of metal surfaces in general, its greatest fouling from rifle, gun barrels,

present utility is in con- 1 of cupro-nickel and other coatings from iron and steel generally.

It is well known thatv gun barrels after considerable use become fouled with copper or cupro-nickel depo the action of the gu sits or coatings due to the bands ing ammonia water,

liquid d remove un esirable ammomum persulfate, and ammonium carbonate. This solution apparently acts in the following manner: the ammonium persulfate oxidizes the copper and .nickel, and the resulting oxids are dissolved in the mixture of ammonium hydroxid and ammonium carbonate, thus removing the metal fouling. Ammonium persulfate in neutral or acid solution would oxiize the steel of the rifle barrel; but the rather large excess of free ammonia keeps the solution strongly alkaline and prevents injurious corrosion'of the steel.

The above mixture, while eflicient, has several disadvantages. In the first place, the complete solution decom oses in a short time and hence must be freshIy prepared for use.

' Again, one of the essential ingredients, am-

monia water, must be transported in liquid form and is. a substance which rapidly loses its strength unless kept carefully stoppered and in a cool place. Breakage of the ammonia water containers is also a serious difficulty. Furthermore, preparation from the separate ingredients involves weighing and measuring which is not only troublesome and wasteful of material, but in the hands of men unaccustomed to such operations, frequently results in mistakes. Improper proportions of the ingredients can easily produce a solution which may have little'or no effect on metal fouling but which may have decidedly injurious eifects on the guns.

The present invention therefore consists in obviating the foregoing difficulties and objections by using substances which are solid and easily kept and transported, but which, when properly mixed with water, react to give a liquid which removes cupronickel and similar deposits without injuring the steel of the gun barrel, or other metal object to be cleaned. V

Stated generally, the invention involves the preparation and use of the necessary chemical ingredients in the form of solid substances put up in separate measured units of some kind, these units most conveniently taking the form of compressed tablets containing predetermined quantities of the ingredients. For example, one unit may comprise a chemical containing oxygen in active condition and therefore adapted, upon addition of water, to oxidize the copper or cupro-nickel fouling in a gun barrel. This same unit most desirably embodies also what may be conveniently termed a latent or potential solvent for the metal oxids resulting from the attack on the fouling, such latent or potential solvent being a substance which, upon addition of water, or another reagent, develops the necessary solvent action. Broadly speaking, such potential solvent substance may be present either as an integral part of the compound containing active oxygen, or as another chemical compound admixed therewith, the latter being generally more desirable and convenient in actual practice. Another unit, to be used in conjunction with the first mentioned unit, should comprise in solid form, such as a tablet, an alkaline reagent which, upon reaction in aqueous solution with the constituents of the first unit, will aid in developing the potential solvent action before mentionedf Ordinarily, only the two units mentioned are necessary in practicing the invention. The chemical contents of the tablets or other forms constituting the two separate units being predetermined with the requisite accuracy, it is only necessary to bring together the separate units in proper predetermined proportions, in the presence of the necessary amount of water, to produce an eflective cleaning liquid of the character described.

In order to afford a more complete understanding of the invention, a typical embodiment thereof Will now be described in detail. It will be assumed that the completed cleaning solution when ready for use is to contain ammonium persulfate, ammonium sulfate, and ammonium hydroxid in proper proportions to rapidly attack and dissolve cupro-nickel gun fouling, and at the same time not to undesirably afiect the steel of a gun barrel. Ammonium persulfate and numerous other ammonium salts are solids that can be easily kept and transported when dry. Furthermore, most ammonium salts, among which ammonium sulfate ofl'ers special advantages, do not react with ammonium persulfate when mixed therewith in dry condition. Accordingly, one of the separate units in the present instance, consists of a dry uniform mixture of ammonium persulfate and ammonium sulfate compressed into tablets. In order to ensure strength and coherence of these tablets, a small amount of a suitable binder such as neeaeeo sugar or dextrin may be incorporated with the salts; and a small amount of stearic acid or other lubricating agent may also form a part of the mixture in order to effect ready separation of the tablets from the forming dies. Such additions are, of course, common practice in the tablet-making art.

The other separate unit in the present instance comprises tablets of a caustic alkali, caustic soda (sodium hydroxid) being entirely suitable for this purpose. Caustic alkalies such as sodium hydroxid and potassium hydroxid, can be readily kept and transported without alteration if protected against moisture. The caustic soda tablets may of course also comprise binding and lubricating ingredients.

The proportions of the ingredients used in preparing the above described tablets may vary considerably in practice. In a typical embodiment of the invention found to be especially advantageous, the tablets of the first unit may each weigh about 2.25 grams, and may contain 0.75 gram of ammonium persulfate and 1.25 grams of ammonium sulfate, the balance consisting of binder and lubricant. That is, the proportion of persulfate to sulfate is about 3 to 5 in this instance, and in general it will be found best to have the sulfate constitute the greater part of the mixture. For best results, these tablets should not contain more than 3 per cent of matter insoluble in water, and not more than 0.1 per centof matter insoluble in water after ignition. The tablets of the second unit may be of about the same weight and contain about 2 grams of caustic soda or sodium hydroxid. Most desirably, the caustic soda tablets should not contain more than 0.5 per cent of matter insoluble in water, and not more than 0.1 per cent of matter insoluble in. water after ignition. In using tablets of this particular description to remove metal foulin from a rifle barrel, for example, a very e ective solution is obtained by dissolving four of the ammonium persulfate ammonium-sulfate tablets and one caustic soda tablet in from-30 to 35 cubic centimeters of water. The material dissolves completely except for small quantities of binder and lubricant which may be disregarded. The fixed alkaline reagent, caustic'soda in this instance, liberates ammonia from both the ammonium persulfate and the ammonium sulfate with formation of sodium sulfate, the resultant solution being strongly ammoniacal and highly oxidizing in character. The necessary amount of this solution is introduced into the gun barrel, the breech of which has been previously plugged, and is allowed to remain in the gun long enough to ensure the necessary cleansing action. As a rule this is efl'ected in from 15 to 30 minutes.

e ammonium hydroxid, together with any of container breakage excess ammonium sulfate, readily dissolves the cupro-nickel oxids formed by the 0x1- dizing action of the ammonium persulfate on the metal fouling.

The tablets comprising the two units are of course kept in separate tightly closed containers, and can be readily issued in the field or elsewhere when it is necessary to clean the gun barrels. It is simply necessary to take the necessary number of tablets of each unit and add to them the specified amount of water in order to prepare the cleaning liquid; and hence-no special skill is required and the liability of mistake in making up the liquid is practically elnmnated. Furthermore, since all the chemical ingredients are in solid form, they are easily transported and handled without the danger attending transportation of aqua-ammonia, and with a very great reduction in amount of cargo space required.

It is evident that the ammonium. hydroxid required in the completed cleaning liquid could be generated from ammonium persulfate alone without the use of an ammonium salt admixed therewith; but as ammonium persulfate is an expensive chemical, marked economy can be effected by using elther ammonium sulfate or some other ammonium salt in admixture therewith. For this purpose, ammonium nitrate or ammonium chlorid, for example, can replace ammonium sulfate in the formula above given, since neither of these salts reacts upon ammonium persulfate in dry mixture therewith; but in practice we find ammonium sulfate ,particularly efficient and desirable, and it is also relatively inexpensive. v Ammonium carbonate is less desirable for this purpose than the sulfate, chlorid or nitrate, because it is not so stable. Instead of ammonium persulfate, it is also possible to use other soluble persulfates, such as sodium ersulfate, or potassium persulfate, or mlxtures of these with each other or with ammonium persulfate. When sodium or potassium persulfate is used, it is of course essential to employ with it an ammonium salt to furnish ammonium hydroxid by reaction with caustic alkali in the complete liquid mixture. Mixtures of two or more ammonium salts may re lace the single ammonium salt; and, similar y, mixtures of caustic alkalies, such as sodium and potassium hydroxids may be used in place of a single caustic alkali.

It is to be noted that although ammonium hydroxid generated by mixture of the separate solid reagents with water as described, is the most convenient solvent to employ for copper and nickel oxids, the invention in its broader aspects is not restricted thereto. For example, salts of substituted ammonium compounds which will liberate solvent ammonium bases upon reaction with an alkali or an alkaline reagent, may be employed in conjunction with the persulfate or other persalt; but ordinarily there is no advantage in usingsuch salts over the use of the more common ammonium compounds.

Persulfates are particularly eflicient as oxidizers in metal cleaning liquids of the haracter here in question. Other oxidizing agents may be employed under some conditions, however, such as perselenates, for example, but persulfates, and especially ammonium persulfate, are distinctly preferable in ractice.

hat we claim is:

1. As a new composition of matter useful in cleaning gun barrels and other metal surfaces, a substantially dry mixture comprising ammonium persulfate and ammonium sulfate, in proper proportions to give a suitable metal-cleanin solution upon treatment with water and a xed alkaline reagent.

2. As a new composition of matter useful in cleaning gun barrels and other metal surfaces, a substantially dry mixture comprisammonium persulfate, and ammonium su fate, the ammonium sulfate constituting the greater part of the mixture.

3. As a new composition of matter useful in cleaning gun barrels and other metal surfaces, a substantially dry mixture comprising about 3 parts by weight of ammonium persulfate and about 5 parts by weight of ammonium sulfate.

4. As a new composition of matter useful in cleaning gun barrels and other metal surfaces, a substantially dry mixture comprising a soluble persulfate and an ammonium salt, in proper proportions to give a suitable metal-cleani solution upon treatment with water and a xed alkaline reagent.-

5. As a new composition of matter useful 7. As a new composition of matterv useful in cleaning gun barrels and other metal surfaces, a substantially dry mixture comprising an oxidizer for "copper and nickel, and a potential solvent for copper and nickel oxids.

8. Material for use in cleaning gun barrels and other metal surfaces which comprises separate solid substances in the form of measured units adapted when brought together with sufiicient water or other appropriate solvent, to give an ammoniacal oxidizing liquid of the desired character. V 9. Material for use in cleaning gun barrels and other metal surfaces which consists of the necessary chemicals in solid condition put up in two separate units, such as tablets or other convenient form, adapted to be mixed in a predetermined manner with water to give an ammoniacal oxidizing liquid.

10. Material for use in cleaning gun barrels and other metal surfaces which consists of two separate solid substances prepared in convenient form such as tablets, one of which comprises a mixture of a soluble persulfate such as ammoniumpersulfate, with an ammonium salt such as ammonium sulfate; while the other of said substances comprises a caustic alkali such as sodium hydroxid.

11. Material for use in cleaning gun barrels and other metal surfaces which consists of two kinds of tablets; one kind containing about 0.75 gram of ammonium persulfate and 1.25 grams of ammonium sulfate; and the other kind containing about 2.00 grams of caustic soda. 1

12. The process of preparing a liquid for cleaning gun barrels and other metal surfaces which comprises reacting with a fixed alkaline reagent upon a per-salt and an ammonium compound in the presence of water.

13. The process of preparing a liquid for cleaning gun barrels and other metal surfaces which comprises mixing ammonium persulfate, ammonium sulfate, and a caustic alkali, with water.

14:. A compound for removing fouling from gun barrels and the like, comprising ammonium per-sulphate, ammonium sulfate and sodium hydroxide in a reacting mixture at the time of introduction into the gun barrel.

In testimony whereof we hereunto affix our signatures.

PERCY H. WALKER. JOHN H. BOWER. 

